Gear lubricant



Patented June 19, 1934 PATENT OFFICE 1,963,239 GEAR wamcm George M. Maverick, Elizabeth, N. 1., asslgnor to Standard Oil Development Company No Drawing. Application April 15, 1931,

Serial N0. 530,433

2 Claims. (01. 87-9) This invention relates to heavy lubricants and a method for preparing them. More particular- 1y it relates to gear oils such as those used for lubricating transmission gears, differential gears and other similar.mechanisms which require a heavy lubricant that must remain fluid and plastic at relatively low temperatures, and in one phase the invention relates to a gear oil containing a specific depressant of channeling, as will be 10 more fully hereinafter described.

I have discovered that by incorporating these heavy lubricants with certain unctuous synthetics, for example heavy condensation products of paraflinic and aromatic hydrocarbons, the plas- 15 ticity and fluidity of the lubricants at low temperatures is markedly greater than that of the normal heavy lubricant. The method of prepar ing the modified lubricants and the nature of the unctuous synthetics will be fully understood from go the following description.

The term unctuous synthetic as used here and in the claims will be understood to mean a heavy hydrocarbon condensation product prepared from bons having a molecular weight of at 35 least 170 and containing at least 13.5 to 15 parts of hydrogen for each 100 parts of carbon, the

hydrogen content being the higher thelower the molecular weight. Open-chain hydrocarbons, such as the paraiilns are preferable as starting materials for the preparation of these synthetics, and especially valuable products are obtained by condensing the open-chain hydrocarbons in the presence of cyclic or olefinic hydrocarbons. The unctuous synthetics are characterized by high 35 viscoaty indices, generally over 100, high flash points, generally over 500 F., and high Saybolt viscomties at 100 F., generally over- 1000, and.

ranging as high as 2000, 5000, 10,000 or 20,000

seconds or more. They also have high molecular 4o weights and are.in general'very viscous. The

methods by which they may be prepared will be described below.

The modified lubricants may be prepared as follows. A heavy hydrocarbon oil with Baybolt l viscosity at 210 F. between say 100 and 200 seconds or higher is heated to a temperature of about 150 to 180 F. and from 2 to or more by weight of unctuous synthetic is added. On cooling, the modified oil remains homogeneous and 50. the unctuous synthetic does not/show any tendency to separate out. It,is preferable to add about 2 to 5% of the unctuous synthetic, but

larger amounts, say 10 to or more may besome gear oils not subject to extreme serviceconditions it maybe feasible to use less than 2% of the unctuous synthetic, the proportion ranging as required downwardly even to a fraction of 1%.

The modified lubricants have greater plasticity so and fluidity at low temperatures than the unmodifled oils, and for this reason the gear shifting effort, drag resistance and tendency to channel when the modified lubricants are cold, as in starting, are greatly reduced. In cold weather par- 05 ticularly, or where the oils are used in low temperature work, the increased plasticity and fluidity at low temperatures of the modified oils is of great advantage. It makes the handling and pumping of the lubricant easier, it reduces the power loss due to friction of the moving parts, it results in less wear and abrasion on the gears,, and reduces the operating temperature in the gear housings. Moreover, the tendency of ordinary gear lubricants to channel, that is to become so viscous that the gears cut channels in the oily mass instead of spinning in continuous contact with fluid oil, is very marked at low temperatures. By the addition of small ammmts of the unctuous synthetic the channeling temperature is lowered from 10 to 15 F. or more.

a It should be particularly noted that only small amounts of the'unctuous synthetic are required to serve eflfectually as an anti-channelant or depressant of channeling, as the effect may be termed. This, of course, is a very different result from that obtainable by adding an ordinary thinner or thinning oil such as kerosene. The unctuous synthetic cannot, of course, be classed as a diluent of this type since it doesnot reduce the lubricating qualities of the oil as in itself the unctuous synthetic preferably is produced of a character exhibiting excellent lubricating values. Looking at the modified lubricant from one standpoint it may be regarded as containing a wax protective colloid capable of substantially reducing the critical temperature of congelation.

In the case of compounded oils, where 2, 5, '1, 10% or more of metallic soaps, such as lead, sodium or aluminum oleates or stearates is added to the straight base mineral oil, the solubility of the soaps in the oil is not very reat. It is essential, however, to keep them in solution to prevent them settling ,out and calring on the moving parts causing undue abrasion and wear. Incorporating unctuous synthetic with such compounded oils appears to aid in retaining these soaps in solutionjas little as about 2% of the unctuous synthetic being eifective for this purpose; In some caseathc addition of the unctuous 110 used to catalyze the chlorination.

synthetic also decreases "the foaming of the oil on agitation.

The synthetic to be added to the heavy lubricat ing oil may be prepared in a variety of different ways and from a number of different materials.

One type of unctuous synthetic is prepared by condensing naphthalene on chlorinated paraiiin in the presence of A1C13. The paraffin wax is chlorinated by direct addition of chlorine until about 10-15% by weight of .chlorine has been added. The chlorination is preferably carried out above the melting point of the paraffin but below the decomposition temperature of the chlorparafifin, say between about 180 and 300 F. and iodine crystals or sunlight, or both may be The chlorparafiin is then dissolved in a highly saturated hydrocarbon oil preferably of the kerosene range and naphthalene is added to this solution. About 20 parts by weight of naphthalene to about 100 parts of chlorparaffin is a satisfactory proportion. The resulting solution is then agitated thoroughly by mechanical or other stirring means and heated to a temperature between about and 175 F., between 100 and 110 F. being preferable. While agitated at this temperature anhydrous aluminum chloride is slowly added over a period of from 4 to 6 hours, until about 7 to 8 partsby weight havebeen added in all. The reaction is allowed to continue then for from 4 to 24 hours longer. It is preferable to allow the reaction to proceed without the application of heat or refrigeration.

When the reaction is complete, the sludge is separated from the oil by settling, centrifuging, or other means. The clear oil is then treated with concentrated sulfuric acid and clay. After removing the clay the oil is distilled either by fire and steam or by vacuum distillation. The distillate comprises the light mineral oil solvent used, some light lubricating oil and a small amount of unconverted wax. The residue is the desired unctuous synthetic. The following is a typical inspection of a synthetic prepared in this way:

Gravity A. P. I 22.1 Saybolt viscosity 100 F 4777 see. Saybolt viscosity 210 F 269 sec. Viscosity index 110 Flash 580 F. Carbon 1.08% Color, Robinson 5 /2 Chlorine 0.031%

It will be understood that the proportions of materials used and the conditions of treatment may be varied considerably with equally satisfactory results, and that the resultant unctuous synthetic may vary therefore to some extent in characteristics. Unconverted wax, recovered solvent, and wax obtained from the sludge may be returned to the process.

An unctuous synthetic may be prepared from chlorinated paraffin and benzol by substantially the same method. An inspection of such an oil follows:

Anunctuous synthetic prepared from chlorinated parafiin and an aromatic gas oil fraction has the following inspection:

Gravity A. P. I 21.7 Saybolt viscosity 100 F 5200 see. Saybolt viscosity 210 F 268 sec. Flash -1 565 F. C'arbon 3.054%

Another type of unctuous synthetic may be prepared without the useof aromatic compounds. This is made by condensing a cracked chlorinated parafiin in the presence of aluminum chloride. Crude scale wax is chlorinated to about 10 to 25% by weight chlorine, and is then passed through a heating coil at a temperature of about 600 to 750 F. preferably in the presence of a catalytic material such as BaClz. At the high temperature, hydrogen chloride is split off, leaving an unsaturated product with only about 3% chlorine content. This unsaturated product is then diluted with a light mineral oil solvent and is condensed in the presence of aluminum chloride. The kind of unctuous synthetic obtained depends upon the chlorine content of the chlorinated parafiin. Inspections of synehetics obtained from chlorinated paraffin containing 10 and 25% of chlorine by weight follow:

, Chlorparafiin Chlorparaflin containing containing 10 25% Cl: 10% Oh Gravity A. P. I 26.4 29.8 Saybolt viscosity 100 F. 1630 see 3000 sec. Saybolt viscosity 210 F 167 sec 234 sec. Viscosity index. 128 117 lash 485 F 620 F. Carbon 1.53% 1.069 Pour 70 F 80 F.

Still another type of unctuous synthetic may be prepared by condensing a chlorinated fatty acid such as stearic acid with benzol, naphthalene or other aromatic compounds in the presence of aluminum chloride.

The following examples willillustrate the effect of adding small amounts of unctuous synthetics to heavy lubricants.

A straight transmission oil is run in a Chevrolet transmission, first without any synthetic added and then with 2% unctuous synthetic added. The results are as follows:

With 2? Straight trans- Demon; mission on synthetic Gear shift effort 307 lbs. secs. 189 lb. secs. Starting drag 26 lbs. 20 lbs. Drag resistance to spin dynamometer at 60 R. P. M 49% lbs. 37% lbs.

The results of other tests on the two oils are as follows: Temperature at which channeling occurs 12 F. 2 F. Penetration test at 13 F. Time for steel bar 9% long, 541;" diameter to penetrate 1 inch into oil 74 secs. 10 secs. Penetration test at +33% F. Time for bar to penetrate ls of an inch 200 sees. 95 secs.

The penetration testat -14? F. on a com- 1 pounded oil containing 10% lead oleate showed that 85 seconds was required for the bar to penetrate 1 inch. When 2% unctuous synthetic. was added to this oil only 42 seconds were required for the same bar to penetrate 1 inch.

These tests uniformly show that the addition of small percentages of unctuous synthetic of the nature described above to heavy lubricants materially increases the fluidity and plasticity of such lubricants at low temperature.

1,968,989 Although the beneficial eiiect of the addition mai operating temperatures. The following comparison of the inspection of a transmission oil before and'aiterthe addition of 2% unctuous synthetic shows how little the synthetic ailfects the normal characteristics 01' the lubricant:

t hm unctuous oll synthetic Gravity, A. P. I. 110 01.9 Saybolt viscosity 6 100' F. ma mo Baybolt viscosity 6 210' IL. 112 114 Pour w 15 15 The unctuous synthetics may also be added in small quantities to heavy hydrogenated lubricants, that is heavy oils with Saybolt viscosity at 210 1". above about 100 obtained by the hydrogenation oi heavy residues, topped crudes, heavy lubricating distiliates and similar heavy fraccharacterized by high pour-points and the addi-. tion of unctuous synthetics to such lubricants may therefore be of particular advantage.

The term gear oil" is used in the following claims to designate a heavy fluid or plastic lubricant with a Saybolt viscosity above about 100 seconds at 210 F. v

. This,invcntion is not limited by any theory of 'the mechanism of the eifect of unctuous synthetics on heavy lubricants nor by any details t given merely by way 01 illustration, but is limited only by the'iollowing claims in which I wish to claim all novelty inherent in the invention.

1. Lubricant composition comprising a gear oil incorporated with a few per cent. of an unctuous synthetic depressant of channeling comprising a hydrocarbon condensation product having an initial molecular weight of at least 170 and containing at least 13.5 parts oif-hydrogen per 100 parts of carbon and a metallic soap soluble in said composition.

2. Composition according to claim 1 containing not more than about 10% ot a metallic soap 0! .a fatty acid. tions. The hydrogenated oils are. in generai- GEORGE u. MAVERICK. 

